Guanethidine is an antihypertensive compound that competes with norepinephrine for transport into presynaptic terminals of adrenergic neurons by the norepinephrine transporter.1 Once guanethidine has entered the nerve, it becomes concentrated in synaptic vesicles, depleting endogenous norepinephrine, and thus, reducing the release of norepinephrine in response to action potentials.1 Guanethidine’s actions are restricted to peripheral nerve terminals because its basic guanidine group does not allow passage through the blood brain barrier.1 Its use has been explored in the relief of chronic pain caused by complex regional pain syndrome.2
1.Gerber, J.G., Freed, C.R., and Nies, A.S.Antihypertensive pharmacologyWest. J. Med.132(5)430-439(1980) 2.Livingstone, J.A., and Atkins, R.M.Intravenous regional guanethidine blockade in the treatment of post-traumatic complex regional pain syndrome type 1 (algodystrophy) of the handJ. Bone Joint Surg. Br.84(3)380-386(2002)